Table 2. Mean leaf parameters at experimental CO2 levels in G1-1 and G1-2.
Mean leaf parameters at 66 and 73 experimental days. The leaf response clustered into two distinct stages (G1-1 and G1-2) in the first growing season (G1). Error in standard error of the mean. Tests of significance were two-tailed Student’s T-tests assuming unequal variance.
| Parameter (unit) | CO2 (ppmv) | G1-1 (66 days) | Change | G1-2 (73 days) | P-value |
|---|---|---|---|---|---|
| LA (cm2) | 150 | 0.88 ± 0.13 | 0.59 ± 0.07 | <0.002 | |
| 450 | 0.94 ± 0.12 | > | 0.66 ± 0.06 | <0.002 | |
| 800 | 1.37 ± 0.15 | 0.65 ± 0.09 | <0.002 | ||
| CA (μm2) | 150 | 1115.41 ± 172.17 | 962.21 ± 77.08 | ns | |
| 450 | 945.15 ± 60.03 | > | 998.02 ± 33.42 | ns | |
| 800 | 1212.69 56.91 | 883.26 ± 61.3 | <0.02 | ||
| DE (n mm-2) | 150 | 968.12 ± 70.06 | 1588.69 ±84.18 | <0.001 | |
| 450 | 881.99 ± 76.30 | < | 1497.45 ± 135.64 | <0.001 | |
| 800 | 1013.66 ±61.72 | 1286.29 ± 86.96 | <0.001 | ||
| DS (n mm-2) | 150 | 127.54 ± 12.53 | 162.82 ± 9.24 | <0.002 | |
| 450 | 106.83 ± 9.6 | < | 163.42 ± 21.46 | <0.002 | |
| 800 | 119.88 4.8 | 147.74 ± 11.35 | <0.002 | ||
| LP (μm) | 150 | 20.86 ± 1.31 | 18.46 ± 0.5 | ns | |
| 450 | 26.82 ± 0.96 | > | 17.82 ± 0.66 | <0.003 | |
| 800 | 21.71 ±0.56 | 17.41 ± 0.52 | <0.003 | ||
| gsmax (mol m-2 s-1) | 150 | 1.05 ± 0.06 | 1.09 ± 0.06 | ns | |
| 450 | 1.17 ± 0.05 | 1.08 ± 0.09 | ns | ||
| 800 | 1.1 ± 0.05 | 0.92 ± 0.06 | ns | ||
| SI (%) | 150 | 11.56 ± 0.049 | 9.31 ± 0.16 | <0.04 | |
| 450 | 10.97 ± 0.52 | > | 9.8 ± 0.49 | ns | |
| 800 | 10.74 ± 0.57 | 10.32 ± 0.24 | ns |